diff --git a/src/substrait/textplan/StructuredSymbolData.h b/src/substrait/textplan/StructuredSymbolData.h
index 97f94bbb..676fa211 100644
--- a/src/substrait/textplan/StructuredSymbolData.h
+++ b/src/substrait/textplan/StructuredSymbolData.h
@@ -41,15 +41,18 @@ struct RelationData {
   // Each field reference here was generated within the current relation.
   std::vector<const SymbolInfo*> generatedFieldReferences;
 
-  // Local aliases for field references in this relation.
+  // Local aliases for field references in this relation.  Used to replace the
+  // normal form symbols would take for this relation's use only.  (Later
+  // references to the symbol would use the alias.)
   std::map<size_t, std::string> generatedFieldReferenceAlternativeExpression;
 
   // If populated, supersedes the combination of fieldReferences and
   // generatedFieldReferences for the field symbols exposed by this relation.
   std::vector<const SymbolInfo*> outputFieldReferences;
 
-  // Contains the field reference names seen so far along with the id of the
-  // first occurrence.
+  // Contains the field reference names seen so far while processing this
+  // relation along with the id of the first occurrence.  Used to detect when
+  // fully qualified references are necessary.
   std::map<std::string, size_t> seenFieldReferenceNames;
 };
 
diff --git a/src/substrait/textplan/converter/InitialPlanProtoVisitor.cpp b/src/substrait/textplan/converter/InitialPlanProtoVisitor.cpp
index 17e6f1ce..dfbdf38f 100644
--- a/src/substrait/textplan/converter/InitialPlanProtoVisitor.cpp
+++ b/src/substrait/textplan/converter/InitialPlanProtoVisitor.cpp
@@ -19,7 +19,7 @@ namespace io::substrait::textplan {
 
 namespace {
 
-const std::string kIntermediateNodeName = "intermediate";
+const std::string kIntermediateNodeName{"intermediate"};
 const std::string kRootNames{"root.names"};
 
 std::string shortName(std::string str) {
@@ -90,7 +90,6 @@ ::google::protobuf::RepeatedField<int32_t> getOutputMapping(
       return relation.filter().common().emit().output_mapping();
     case ::substrait::proto::Rel::kFetch:
       return relation.fetch().common().emit().output_mapping();
-      ;
     case ::substrait::proto::Rel::kAggregate:
       return relation.aggregate().common().emit().output_mapping();
     case ::substrait::proto::Rel::kSort:
@@ -100,7 +99,7 @@ ::google::protobuf::RepeatedField<int32_t> getOutputMapping(
     case ::substrait::proto::Rel::kProject:
       return relation.project().common().emit().output_mapping();
     case ::substrait::proto::Rel::kSet:
-      return relation.sort().common().emit().output_mapping();
+      return relation.set().common().emit().output_mapping();
     case ::substrait::proto::Rel::kExtensionSingle:
       return relation.extension_single().common().emit().output_mapping();
     case ::substrait::proto::Rel::kExtensionMulti:
@@ -330,6 +329,7 @@ std::any InitialPlanProtoVisitor::visitNamedStruct(
         SymbolType::kField,
         SourceType::kUnknown,
         type);
+    nameNum++;
   }
   return BasePlanProtoVisitor::visitNamedStruct(named);
 }
diff --git a/src/substrait/textplan/converter/PipelineVisitor.cpp b/src/substrait/textplan/converter/PipelineVisitor.cpp
index 218f798b..d63a6f56 100644
--- a/src/substrait/textplan/converter/PipelineVisitor.cpp
+++ b/src/substrait/textplan/converter/PipelineVisitor.cpp
@@ -118,6 +118,7 @@ std::any PipelineVisitor::visitPlanRelation(
     const ::substrait::proto::PlanRel& relation) {
   auto symbols =
       symbolTable_->lookupSymbolsByLocation(PROTO_LOCATION(relation));
+  // A symbol is guaranteed as we previously visited the parse tree.
   auto relationData = ANY_CAST(std::shared_ptr<RelationData>, symbols[0]->blob);
   switch (relation.rel_type_case()) {
     case ::substrait::proto::PlanRel::kRel: {
diff --git a/src/substrait/textplan/parser/SubstraitPlanRelationVisitor.cpp b/src/substrait/textplan/parser/SubstraitPlanRelationVisitor.cpp
index dc1a0b32..a8273f12 100644
--- a/src/substrait/textplan/parser/SubstraitPlanRelationVisitor.cpp
+++ b/src/substrait/textplan/parser/SubstraitPlanRelationVisitor.cpp
@@ -278,10 +278,12 @@ void addInputFieldsToSchema(
     auto continuingRelationData = ANY_CAST(
         std::shared_ptr<RelationData>, relationData->continuingPipeline->blob);
     if (!continuingRelationData->outputFieldReferences.empty()) {
+      // There is an emit sequence so use that.
       for (auto field : continuingRelationData->outputFieldReferences) {
         relationData->fieldReferences.push_back(field);
       }
     } else {
+      // There was no emit so just access all the field references.
       for (auto field : continuingRelationData->fieldReferences) {
         relationData->fieldReferences.push_back(field);
       }
@@ -594,7 +596,7 @@ std::any SubstraitPlanRelationVisitor::visitRelationUsesSchema(
         auto typeProto = ANY_CAST(::substrait::proto::Type, sym.blob);
         if (typeProto.kind_case() != ::substrait::proto::Type::KIND_NOT_SET) {
           *schema->mutable_struct_()->add_types() = typeProto;
-          // If the schema contains one more types, the structure is required.
+          // If the schema contains any types, the struct is required.
           schema->mutable_struct_()->set_nullability(
               ::substrait::proto::Type_Nullability_NULLABILITY_REQUIRED);
         }
@@ -1161,8 +1163,6 @@ std::any SubstraitPlanRelationVisitor::visitExpressionColumn(
     // TODO -- Update the following when non-direct references are implemented.
     expr.mutable_selection()->mutable_root_reference();
   }
-
-  // visitChildren(ctx);
   return expr;
 }
 
@@ -1990,6 +1990,7 @@ void SubstraitPlanRelationVisitor::applyOutputMappingToSchema(
     common->mutable_direct();
   } else {
     if (!relationData->outputFieldReferences.empty()) {
+      // TODO -- Add support for aggregate relations.
       errorListener_->addError(
           token, "Aggregate relations do not yet support emit sections.");
       return;
diff --git a/src/substrait/textplan/parser/SubstraitPlanVisitor.cpp b/src/substrait/textplan/parser/SubstraitPlanVisitor.cpp
index a5a756a6..e3d47c5a 100644
--- a/src/substrait/textplan/parser/SubstraitPlanVisitor.cpp
+++ b/src/substrait/textplan/parser/SubstraitPlanVisitor.cpp
@@ -511,7 +511,6 @@ std::any SubstraitPlanVisitor::visitFile_detail(
   } else {
     return visitChildren(ctx);
   }
-  // symbol->blob.swap(item);
   return defaultResult();
 }